A number of different theories have been proposed to explain the wide range of symptoms in schizophrenia, including alterations of the dopaminergic and/or glutamatergic systems, abnormal neurodevelopment, and the theory of immune system imbalance.

When discussing the concept of cognitive impairment, many terms are used, including dementia, amnestic disorder, cognitive impairment not dementia (CIND), cognitive impairment associated with normal aging, mild cognitive impairment, vascular cognitive impairment, and vascular cognitive impairment not dementia (VCIND). Although definitions of such terms are clinically important, there is significant uncertainty about associating a given cognitive syndrome with specific neuropathology.1

In recent years, we have learned a great deal about posttraumatic stress disorder (PTSD) and its public health implications. From 9/11 to Katrina and the present Iraq war, PTSD has been in the forefront of health concerns and public policy.